This invention relates to a `breech-block` valve with ceramic plate seals for the delivery of cold or hot water within the context of a tap in sanitary equipment. More particularly the invention relates to a `breech-block` valve of the type having a hollow cylindrical body which is designed to be screwed into a tap body in line with a pipe supplying the water which is to be delivered, and including internally, from the base upwards, an annular seal, a first ceramic plate which is fixed within the body and has at least one hole for the passage of water, a second ceramic plate, resting on and rotating on the first and having at least one hole which can be positioned in line with and at a distance from the hole in the first plate following a quarter turn or a half turn of the second plate, a follower which is rotatably mounted within the body and keyed to the second plate, and an operating spindle keyed to the follower and provided with a manually operated handgrip to control the second plate via the follower, the cylindrical body and the follower also having radial passages for the water to pass towards the delivery outlet of the tap.
This type of valve is first assembled as an independent unit and is then mounted in the body of the tap in question by being screwed in. Known embodiments of such valves however have the disadvantage that they cannot be correctly adjusted for inevitable machining defects and play in the tap body itself. At present in fact these defects and plays can only be taken up by tightening the valve to greater or lesser extent achieved by screwing it into the tap body and therefore can only be achieved by variable squashing of the packing at the base of the valve. Then however the load is transmitted directly to the ceramic plates, altering their original compaction force and their optimum seal and thus making it more difficult to control opening and closing of the valve, in addition to increasing wear on the plates.